Coded carrier conveyor system



July 12, 1966 c. H. VANDER MEER 3,260,349

CODED CARRIER CONVEYOR SYSTEM original Filed March 24, 1961 15sheets-sheet 1 S July 12, 1966 c. H. VANDER MEER 3,260,349

CODED CARRIER CONVEYOR SYSTEM l5 Sheets-Sheet 2 Original Filed March 24,1961 QN n@ M mum m ww www um www om, ,www NMXM Qwmw INVENTOR. (zA Vrd/vH. 144A/aie fik BY f7 A 7mm/Hs July 12, 1966 c. H. VANDER MEI-:R3,260,349

CODED CARRIER CONVEYOR SYSTEM Original Filed March 24, 1961 l5Sheets-Sheet 5 INVENTOR. CLAYTON H. VANDER MEER w r' M A TTPA/E KS' July12, 1966 c. H. VANDER MEER 3,260,349

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CODED CARRIER CONVEYOR SYSTEM Original Filed March 24, 1961 15Sheets-Sheet 5 ELUX /6/x /Zx /x l l V fJ INVENTOR. 42M D c mi 2M/70A H.VANDER MER July 12, 1966 c. H. VANDER MEER 3,260,349

CODED CARRIER CONVEYOR SYSTEM INVENToR. CLAYTON H. VANDER MEER July 12,1966 c. H. VANDER MEER 3,260,349

CODED CARRIER CONVEYOR SYSTEM 'r $07.4 @a 3/ lNI/ENTOR. A CLA YT/V H.[M/ DER M55@ FIG. /0 BY TTOR/VEYS July 12, 1966 c. H. VANDER MEER3,260,349

CODED CARRIER CONVEYOR SYSTEM Original Filed March 24, 196l l5Sheets-Sheet 8 +170 v RES/STGR INVENTOR. CLAYTON H. VANDER MEER WQ@ M ATTORNE K5 July l2, 1966 c. H. VANDER MEER 3,260,349

CODED CARRIER CONVEYOR SYSTEM Original Filed March 24, 1961 15Sheets-Sheet 9 Bw@ M ATTURA/EKS July 12, 1966 c, H. VANDER MEER3,260,349

coDED CARRIER coNvEYoR SYSTEM Original Filed March 24, 1961 l5Sheets-Sheet 10 A TTK/VEYS July 12, 1966 c. H. VANDER MEER 3,260,349

CODED CARRIER CONVEYOR SYSTEM Original Filed March 24, 1961 l5Sheets-Sheet 1l INVENTOR. /v CLAW-0N H. zam/0m MffR M f'flpe/ ATTORA/EYS July l2, 1966 c. H. VANDER MEER 3,260,349

CODED CARRIER CONVEYOR SYSTEM Original Filed March 24, 1961 l5Sheets-Sheet 12 U V T 5 o 638 6/8 Q l/ #0h16 634- f TAKE-OFF 01E' l//CECTUATR-.j

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INVENTOR. l 56 2 7 cLArroA/ H mA/zw Mff BY f 'J A TTRNEKS' July 12, 1966C` H. VANDER MEER CODED CARRIER CONVEYOR SYSTEM Original Filed March 24,1961 15 Sheets-Sheet 13 U V T f5/6 I 5:/466 WM5@ No. 549

T T l-T- Zi/5%' x6 o VAC 5545555 m45@ No.2 602 L i J7 /600 T f- T @gi-2fw" 606 4570/476@ Lili A44/Vid 1- Mien/a3 590 wfg-af; @nf/cf Aan/Aro@{L4/Viz) A 7TORNE V6 July 12, 1966 c. H. VANDER MEER 3,260,349

CODED CARRIER CONVEYOR SYSTEM l5 Sheets-Sheet 14 Original Filed March24, 1961 A TTRNE YS July 12, 1966 c. H. VANDER MEER 3,260,349

CODED CARRIER CONVEYOR SYSTEM l5 Sheets-Sheet l5 Original Filed March24, 1961 A TT' ORNE YS United States Patent O "ice 3,260,349 CGDEDCARRIER CONVEYOR SYSTEM Clayton H. Vander Meer, Wyoming, Mich., assignerto The Rapids-Standard Company, Inc., Grand Rapids,

Mich., a corporation of Michigan Continuation of application Ser. No.98,137, Mar. 24,

1961. This application Oct. 4, 1965, Ser. No. 496,245

Claims. (Cl. 198-38) This application is a continuation of co-pendingapplica-tion Serial No. 98,137, lcd March 24, 1961 which is acontinuation-in-part of .application Serial No. 15,939, led March 18,1960 and entitled Conveyor System, both of which are now abandoned.

This application relates to materials hand-ling systems, and moreparticularly to conveyor systems of the flowing storage type.

In recent years, the materials handling industry has been called upon toprovide equipment for the automation of materials handling in fieldshitherto largely reserved to manual labor. In some 0f these elds, anexample of which is the field of airline baggage handling, it has becomenecessary to provide equipment which can receive goods earmarked for avariety of ultimate destinations at one or more receiving stations inany order and at any time; to deliver these goods over a centralconveying system to one or more destination stations such as the loadingplatforms at an airline terminal which are from time to time associatedwith different carriers or airplanes which carry the goods to theirultimate des-tinations; storing those goods which are fed into thesystem at a time when none of the destination stations is associatedwith a carrier going to their ultimate destination; releasing the storedgoods to a destination station when it becomes associated with a carriergoing to the proper ultimate destination; and returning to theoriginating station the containers for the goods in those cases wheremarking of the goods themselves is impractical or undesirable.

The present invention achieves this result by the use of a llowingstorage or recirculating conveyor which periodically passes all thecoded goods or objects in the conveyor system through a decodingmechanism which causes objects marked with a given code =to be ejectedfrom the recirculati-ng loop toward a destination station when and onlywhen that destination station is ready to accept objectswith that code.

In airline baggage handling, for which the embodiment described in thisapplication is designed, the individua-l baggage items are preferablyplaced on trays equipped with magnetizable slugs onto which a magneticcode can be impressed, the code being representative of the number ofthe ilight onto which the piece of baggage is to be loaded. As long asthe ilight in question has not yet arrived at the terminal, any baggagefor that flight is fed into the flowing storage or recirculating portionof the conveyor system. When the Hight in question arrives, themechanism is set up to select from all the baggage in the conveyorsystem those pieces which are to go on the flight in question, and toconvey them to the destination station located at the loading platformat which the iligh-t in question is parked. The empty trays are thenreturned to the originating station lor ticket counter after having themagnetic code thereon erased so that they lare reusable for anotherpiece of baggage.

Other aspects of this invention are concerned with novel mechanical andelectrical devices and circuitry which enable the system t-o function inthe manner described.

It is therefore the basic object of this invention to provide a conveyorsystem in which objects can be selectively conveyed from an originatingstation to a destination station if the destination is ready to receivethem, or stored 3,260,349 Patented July 12, 1966 and periodicallyrecirculated for eventual delivery if and when the destination stationbecomes ready to receive them.

It is a further object of this invention to provide a closed-loopconveyor with selectably codable paths in which a coded object isautomatically recirculated until the code of one of said paths is madeto correspond to the code of the object.

It is a still further object of this invention to provide a system ofthe type described above in which magnetic destination codes can berepeatedly impressed on freecycling, reusable containers.

It is another object of this invention to provide such a system in whichthe magnetic code is impressed on elements positioned longitudinallywith respect to the direction of travel of the container.

It is still another object of this application to provide an electricalcontrol structure and circuitry for achieving control of the conveyorsystem in accordance with the principles described above.

These and other objects of this invention will become apparent from aperusal of the following specification, taken in connection with theaccompanying drawings in which:

FIG. 1 is a schematic layout diagram of the system of this invention;

FIG. 2 is a schematic representation of the basic physical organizationof the ilowing storage system;

FIG. 3 is a perspective view of a tray which may be used in the systemof this invention;

FIG. 4 is a schematic layout diagram of the ticket counter portion ofthesystem;

FIG. 5 is ya perspective view of the encoder console;

FIG. 6 is a cutaway perspective view of the encoder head;

FIG. 7 is a vertical section taken along line VII--VII of FIG. 6;

FIG. 8 is an encoding chart;

FIGS. 9, 10 and 11 constitute a circuit diagram of the encoder;

FIG. 12 is a perspective view of a decoder head;

FIG. 13 is a transverse vertical section of a decoder module along lineXIII- XIII of FIG. 12;

FIG. 14 is a vertical longitudinal section of 4a decoder module alongthe line XIV-XIV of FIG. 13;

FIG. 15 is a perspective view of a preselector console;

FIG. 16 is an enlarged schematic view showing the physical layout of theactuator portion of the system;

FIG. 17 is a circuit diagram of the decoder;

FIG. 18 is a lcircuit diagram of the preselect-or;

FIG. 19 is a block diagram showing how FIGS. 17, 18, 20 and 21 littogether;

FIG. 20 is a circuit diagram of a delay type `of cornparator-actuatorunit;

FIG. 2l is a circuit diagram of a rotary type 0f comparator-actuatorunit;

FIG. 22 is a front elevation of a magnetic rotary mem ory device as usedin the circuit of FIG. 21;

FIG. 23 is a front elevation of the eraser head;

FIG. 24 is a ilux graph of the eraser unit;

FIG. 25a is a block diagram of a flow control system for the outgoingside ofthe ticket counter;

FIG. 25b is a like block diagram for the incoming side ofthe ticketcounter;

FIG. 26 is a block diagram showing the manner in which FIGS. 9, l0 and11 fit together;

FIG. 27 is a block diagram showing how FIGS. 25a and 25b t together;

FIG. 28 is a schematic view of the tray spacing mechanism; and

FIG. 29 is a schematic view of a decoder module illu( strating itssequence of operation.

3 Basic concepts 1.l-FIowing Storage".-Basically, the invention in itsbroadest aspect is concerned with a conveyor system having anoriginating station, a recirculating loop or flowing storage section,and a destination station. Traveling over this conveyor system areobjects on which various destination codes have been impressed. Thedestination station can be made receptive to objects bearing a certaincode from time to time, and to objects bearing other codes at othertimes. Objects fed into the system at the originating station at timeswhen the destination station is not ready to receive them areperiodically recirculated through the flowing storage section until suchtime as the destination station becomes ready to receive them.

1.2-CIsed-Ioop c0nvey0r.-The partcula-r embodiment of the inventionshown in this application embodies the concept of a closed-loop conveyorforming a primary loop from an originating station to a destinationStation and back to the originating station, a recirculating loop beinginterposed in the portion of the primary loop lying between theoriginating station and the destination stations. Coded objects areadapted to circulate on the conveyor system and the destination stationsare associated with selectively codable paths so that each destinationstation can be made receptive from time to time to articles bearingselected codes.

1.3-Free-cycl1'ng codable containers-This invention Pteaches the use ona closed-loop conveyor of free-cycling, article-carrying containerswhich are not in any way attached to the conveyor and can be placed onand removed from the conveyor at will. These containers carry aplurality of code-registering members which can be periodically encoded,decoded, and erased, and which are positioned one behind the other in adirection parallel to the direction of movement of the container whileit passes through the encoding, decoding, or erasing means.

1.4-Basc control structure-The basic electrical control structure ofthis invention consists of an encoding or writing unit, a decoding unitsometimes referred to as a reading or sensing unit, and an erasing unit,coupled with automatic routing means for routing coded objects along aconveyor system in accordance with the code demanded by various branchesof the conveyor system, and with flow control means to assure properspacing of the objects on the conveyor and to assure a continuous supplyof objects at the conveyors originat- 'ing station.

1.51-Encoder.-The encoder of this invention consists basically of akeyboard-operated unit which presets an electric circuit so as tomomentarily energize predetermined ones of a plurality of magnetizingcurrent sources at the exact moment when an object to be coded isprecisely in a predetermined position with respect to the encodingmechanism. In a preferred embodiment of the invention, special circuitryis provided so as to enable the keyboard to be of the ten-key type. Thismay be accomplished by an encoding system using a separate vbinaryexpression of each digit of a decimal code number. The binary systememployed may be such that any digit of a decimal number can be expressedin the binary system by the energization of not more than two electricalcircuits.

1.52-Aut0111atc spacing-This invention teaches the use of a spacingdevice which automatically provides a minimum spacing between successiveobjects conveyed on a conveyor prior to the passage of such objectsthrough a code sensing device. The spacing is accomplished by conveyingthe objects first over a conveyor section driven at a firstpredetermined speed and immediately thereafter over a second conveyorsection driven at a much greater speed. The conveyor is so constructedthat an object traveling along it is accelerated almost instantly to thespeed of the second conveyor portion as soon as its leading edge touchesthe second conveyor portion. During the interval of time betweenthemoment at which the leading edge of the first object touches thesecond portion of the conveyor and the time at which the leading edge ofthe next following object touches the second porA tion of the conveyor,the first object moves faster than the next following object and thusbecomes spaced therefrom. The amount of spacing can be controlled byvarying the relative speed of the second portion of the conveyor withrespect to the first portion thereof.

1.53-Decoder.-This invention provides a novel decoding rcircuit fordecoding a signal impressed on a moving object, the components of thesignal being positioned in sequence along a line .parallel to thedirection of movement of the object. More specifically, in the circuitof this invention, sensing elements are provided in the decoding unitwhich can respond instantaneously to the passage of a signal-bearingelement; and the decoding circuit is accurately actuated only during afraction of the minute time inten/al during which the object is in exactregister with the decoding device by actuating the decoding circuit onlyduring the time interval of movement of the contacts of a single switchbetween their two operative positions. This permits accurate decoding ofobjects traveling at speeds not heretofore possible.

1.54-Aut0nwtic switching lockout-Because it iS conceivable, in aconveyor system of the type described, that coded objects may beconveyed past the decoding mechanism while the code for a particulardestination station is in the process of being changed, the presentinvention provides circuitry by which the manipulation of any of thecode setting controls at a destination station automatically deactivatesthe routing mechanism associated with that destination station until itis manually placed back into service. This is accomplished by providingan extra wiper on al1 code setting switches of a preselector, andconnecting together al1 the contacts wiped by these wipers. The wipersare then connected into a circuit which is broken each time the wiper isbetween two contacts, i.e. each time any of the code setting switches ismoved. Breaking of the Wiper circuit can then be made to causedeactivation of the takeoff device associated therewith. In this manner,misdirection of an object is prevented should the object pass thedecoding mechanism at a time when one of the selector switches on apreselector has been set to a new code but the others have not yet beenmoved.

15S-Selective :akami-Selective take-off means are provided by thisinvention to remove coded objects from a conveyor at a plurality ofdistinct locations while using only a single decoding mechanism forsensing the code on the conveyed object. This function is achieved byproviding one or more memory circuits associated with one or more of thetake-ofi mechanisms. The common feature of the circuits, of whichseveral embodiments are shown and described herein, is that they enablethe decoding mechanism to sense the code of a coded object travelingalong the conveyor before the routing of the immediately precedingobject has been completed. The memory circuits shown herein are thedelay type and, rotary type, respectively. The delay type of memorycircuit causes the object to be ejected a predetermined time after itscode has been sensed. The rotary type of memory circuit causes theobject to be ejected after it has traveled a predetermined distance fromthe point of sensing.

1.56-Erf1ser.-In accordance with this invention, an eraser is positionedadjacent the return portion of a closed loop conveyor to erase themagnetic code markings impressed on the longitudinal flanges of reusablecontainers traveling along the conveyor loop. The eraser of thisinvention is adapted to embrace the flange containing the magnetizedelements of the container and to subject them during their motion to analternating flux field of gradually decreasing intensity. This may beaccomplished by providing a series of oppositely polarized permanentmagnets embracing the path of the flange and having progressivelygreater air gaps.

1.57-Flow control.-Flow control means according to this invention forassuring a steady flow and supply of containers `at the originatingstation of a conveyor system of the type described herein may include areserve storage `area with automatic demand control means which, whenthe reserve storage area becomes depleted, route incoming containersinto the reserve storage area as they become available; a standbystorage area in which Ia few containers are constantly stored inreadiness for immediate use, and which is replenished as necessary fromthe reserve storage area; a loading station where the containers areloaded and which receives a new container automatically as soon as aloaded container is dispatched therefrom; an encoding unit; gate meansto prevent a next following loaded container from entering the encodingunit and to prevent the keyboard of the encoding unit from beingactuated, while a loaded container is progressing through the encodingunit; and gate means for preventing entry of a loaded container into theencoder unit unless there is sufiicient clearance beyond the encoderunit to permit the container to exist from the encoding unit withoutdelay. In the particular embodiment described, the ticket counter areaat which the ow control system is located is at a dilferent level thanthe main portion of the conveyor system, and lifts are consequentlyprovided to raise the containers from the reserve storage area to thestandby storage area and to lower the loaded containers from theencoding unit back down to the main portion of the conveyor system. Forsafety reasons, these lifts may be so programmed that they come to restonly in their uppermost positions.

Structural description 2.1-Fl0wz`rtg Storage seclz'0n.-FIG. 2 shows inschematic form the layout of the basic concept of the flowing storageconveyor system of this invention. objects adapted to travel over theconveyor system 40 enter the conveyor system at the outgoing end 42 ofthe originating station 44 and are conveyed by a lfeed conveyor 46 ontothe main transport conveyor 48. The main conveyor 48 leads past adecoding device 50. If the code on the object being conveyed is the sameas that for which the decoding device 50 is set by the preselector 52,the take-off device 54 will cause the object to be diverted onto thebranch conveyor 56 which conveys it to the destination station 58. Ifthe code sensed by the decoding device 50 is different from that set upby the preselector 52, the takeolf device 54 will not operate and theobject will be conveyed into the recirculating loop 60 from which it iseventually discharged back ont-o the main conveyor 48 through the traiccontrol gate 62 which prevents collisions between objects entering themain conveyor 48 from the feed conveyor 46 and those entering the mainconveyor 48 from the recirculating loop 60. If the objects are reusablecontainers, those that have reached the destination station 58 may beconveyed over a return conveyor 64 past the eraser 66 back to theincoming end 68 of the originating station 44.

2.2-General layout.-A typical embodiment utilizing the concepts of thisinvention is diagrammatically shown in FIG. 1. FIG. 1 schematicallydepicts the conveyor system according to this invention as it would beutilized in handling baggage at an airline terminal. Baggage destinedfor outgoing flights would be received at the ticket counter 72 whichforms part of the originating station 44. The baggage is then placed bythe ticket agent onto a tray such as shown in FIG. 3 which is waiting onthe scale 74, After the baggage has been weighed and the flight numberfor which it is destined has been set up on the keyboard of encoder 76,the tray is released for travel through the encoder 76 and over feedconveyor 46 onto the main conveyor 48. Similar scales 74, encoders 76and feed conveyors 46 are provided at the other positions of the ticketcounter 72. Traffic controllers 62 are provided to prevent collisionsbetween baggage-carrying trays entering the main conveyor 48 fromdifferent Coded feed conveyors 46. Baggage traveling along the mainconveyor 48 eventually reaches the decoding units S0. Each of thedecoding units 50 controls one or more of the take-olf devices 54 whichdivert baggage onto the branch conveyors 56. The specific code whichwill cause actuation of a given one of take-off devices 54 can be set upat will on the preselector 52 associated with that particular take-offdevice and normally located at the destination station 58 to which thebranch conveyor 56 associated with the particular take-olf device 54leads. In the example discussed herein, the destination stations 58would be located at the loading dock 78 at which the airplanes 80 areparked, each destination station 58 being equipped for the unloading ofbaggage destined for the airplane Sil associated therewith. When thebaggage has been unloaded from a baggage carrying tray, the empty traycan be automatically or manually released onto the return conveyor 64.As the trays travel along the return conveyor 64, they pass through theeraser 66 where their destination code is erased. Switches 82 areprovided to route the empty trays into one of the reserve storage areas84 in accordance with the demand for empty trays as determined bysuitable flow control devices.

Any baggage carrying tray which has not been diverted by any of thetake-off devices 54 enters the recirculating loop 6i?. Recirculatio-n ofthe baggage which has entered the recirculating loop 60 can take placecontinuously, or a gate 86 may be provided to periodically release allbaggage stored in the recirculating loop 60 for reprocessing through thedecoding devices 50.

Although the originating stations have so far all been described asbeing at the ticket counter 72, it will be understood that anoriginating station could also be located, for example, in the baggageroom 8S where incoming -baggage is delivered to deplaning passengers atthe baggage counter 90, and continuing baggage is placed onto a tray atthe loading station 92 to be transferred to the outgoing flight forwhich it is destined, via the feed conveyor 94 leading to the mainconveyor 4S.

2.3-T1'ay.-FIG. 3 shows at 100 la preferred embodiment of container ortray which is particularly adapted for use in a conveyor system of thetype descnibed. The tray is preferably formed of wood or otherwear-resistant, nonrnagnetic material to avoid interference with theo-per-ation of the code devices, and is adapted to freely float on therollers 102 of a conveyor 104. The tray 100 has a bottom 106, side walls108, and end walls 110, which together for-m the baggage-receivingcontainer. Side flanges 112 -and end flanges `114 are provided aroundthe -sides and ends of the tray 100 to serve as bumpers. In addition,the side iiange 112 visible in FIG. 3 carries a series of magnetizableslugs 11612 through 116n. As the ytray 100 travels along the conveyor104, the ange 112 carrying the slugs 116 passes through the air gapl 120of the magnetic circuits 118 in the box 122 which may be the encodinghead, decoding head or eraser head.

2.4-Basz'c control Iay0ut.T-he basic control components of the inventionare shown in FIGS. 5, 6, 12, 15, 16, 23, 25 and 29. FIGS. 5 and 6 showthe encoding mechanism which is operated from a keyboard 132 (FIG. 5)and imparts a magnetic code to the slugs 111611 through 111611 of thetray 100 through an encoding head 126 (FIG. 6). The console 124preferably contain-s lan indicator 128 on which the flight number to beencoded is visually displ-ayed; a row of signal lights which indicatethe condition of the apparatus; a tenabutton keyboard 132 on which thellight number can be set up; a release button 1'34 by which a tray 100can be released into the encoding head 126, and 4a cancel button 184 tocancel an entry on the keyboard 132.

The ilight number set up on the keyboard 132 is translated into a binaryor trinary magnetic code by an encoding apparatus which sends a strong,sharp current impulse through the coils 136 of electromagnets 138 at theprecise instant when each of the slugs -116 of the tr-ay 100 is directlybetween the pole pieces of one of the electromagnets 138.

The magnetic code impressed on the slugs 116 of the tray 100 may besensed for routing purposes by a sensing or decoding head 142 (FIG. 12),which may be substantially identical in construction to the encodinghead 126 except that magnetic shields 140 may be provided in the sensinghead to avoid interference between adjacent modules. The sensing head142 has las many modules 421 (FIG. 29) containing magnetic sensingcircuits 144 as there are encoding magnets 138 in the encoding head 126.Like the encoding head 126, the sensing head 142 has a gap `146 throughwhich the flange of the tray is adapted to pass for sensing purposes.

The code sensed by the sensing head 142 is electronically compared to apreselected code set up on a preselector panel 148 which forms part ofthe preselector unit generally designated as 52 in FIG. 1. One panel 148is provided for each branch conveyor or lane 56 (FIG. 1). Bachpreselector panel 148 contains a series of switches 470, 472, 442 onwhich the decimal digits of the flight number to be loaded at thestation 58 associated with the particular preselector 52 can be set up.A start button 152 is provided to energize the preselector 52 after aflight number has been set up on the switches 442, 470, 472, and a lanecoded pilot light 154 indicates that the lane is in use.

The information sensed by the sensing head 14-2 is then fed to adecoder-comparator 156 (FIG. 16) which coopcrates with the preselectorunits 52 to actuate the diverter motor 160 at the appropriate one of thetake-off devices 54 at the exact moment at which a tnay moving on themain conveyor 48 and destined for one of the branch conveyors 56 passesthereover.

After a tray 100 has reached its destination, it is returned to itsoriginating station over the return conveyor 64 (FIG. 1) on which ittravel-s through the eraser 66. The eraser 66 may, for example, consistof permanent magnets 1621, 162, 163 (FIG. 23) of successively opposedpolarity and successively diminishing strength through w-hose air gapsthe flange 1112 of a tray 100 is adapted to travel in the direction ofthe arrow. Of course, other erasing devices, such as a high-frequencymagnetic field (not shown) may be used.

In order to assure a uniform flow of trays 100 in accordan-ce with theneeds of an originating station 74, and to `assure adequate spacing ofthe trays along the main conveyor 48 for accurate sensing, flow controlmeans such as hereinafter described in Section 2.57, and automaticspacing means such as hereinafter described in Section 2.52, may have tobe provided.

2.51.1i1-E11c0de1'; physical lay0ut.-The encoding device according tothisinvention consists of three basic components which may be mountedremotely from one another if desirable. The three basic components arethe encoder console 124 (FIG. 5), the encoder circuit (FIGS. 9, and 11),and the encoding hea-d 126 (FIGS. 6 and 7). In the follow-ingdescription, it should be understood that the encoder circuit describedis the circuit associated with only one of the decimal digits of theflight number (the units digit `in this description), which declmaldigit is expressed by four binary digits. The circuitry associated withthe tens and hundreds digits of the flight number is merely arepittition of the circuitry shown 1n lFIGS. 9. 10 and 11 and has beenomitted for clarity.

2.51.12-E1zc0der; mathematical principle-The mathematical principleunderlying the code circuitry of this invention is, in the preferredembodiment described, based on the separate translation of each digit ofthe decimal flight number into a binary code impressed on four of themagnetizable slugs 116 in the form of either the presence or absence ofmagnetic flux. Although it will be understood that it is immaterialwhether the presence or the absence of a signal is made to signify thebinary digit 1, the preferred embodiment uses the presence of magneticflux as the figure l of the binary system. Of course, a trinary systemcould be used by coding not only by the presence and absence of flux,but also by polarity of flux. The binary system used in the preferredembodiment of this invention differs somewhat from the ordinary binarysystem and is shown in FIG. 8. It will be seen that the digits of thebinary system represent the decimal figures 7, 4, 2 and 1 instead of theusual 8, 4, 2 and l. This system permits the expression of any decimaldigit of the flight number by the energization of not more than twoencoding elements 138. The advantages of this concept are explained inSection 2.51.22. The reason for expressing each digit of the flightnumber separately in binary units, rather than expressing the entireflight number in binary units, is the great simplifciation of theelectronic components made possible thereby. In FIG. 8, the suffixletters of the twelve slugs 116 of tray 100 are shown in the top line.Each blank rectangle 166 means that the slug listed at the head of thecolumn is energized in the expression of the number shown to the left ofthe black box, whereas a white box 168 indicates that the particularslug is demagnetized in the expression of that number.

2.51.21-E11c0der; zead structure-Referring now to FIG. 6, it will beseen that the encoding head 126 contains twelve electromagnets 13811through 13811 corresponding to the twelve magnetizable slugs 116 on tray100. Each of the electromagnets 138a through 13811 is equipped with itsown magnetizing coil 13651 through 13611. An appropriate guide device670 (FIG. 4) is provided to accurately guide the flange 122 of the tray100 through the air gaps of electromagnets 138. The encoding circuit ispreset as hereinafter described, and the appropriate magnetizing pulsesthrough the windings 136 are triggered, when the tray is in alignmentwith the head 126, by the encoder entry trigger switch 306. Provisionsare made by any appropriate means such as the power driven wheel of theguide device 670 to drive the tray past the encoding head 126.

2.51.22-E11c0de1; electronic st1'ucture.-The functioning of the encoderitself can best be understood from -an examination of FIGS. 9, 10 and11. In FIG. 10, the keyboard of the encoder console 124 is once againshown at 132. Each push button of keyboard 132 is in effect asingle-pole double-throw switch. In the rest position of the buttons ofkeyboard 132, the current path which can be traced from the main ofpower supply A-B through section 182 of cancel button 184 (FIG. 5) andthe normally closed contacts 186 of relay 188 dead-ends in bus 190. Assoon as any of the push buttons of keyboard 132, such as push button192, is depressed, however, the current path from bus 190 continuesthrough tap-off 194, push button 192, and tap-off 196 to bus 198. Frombus 198, current continues to flow through wire C and junctions 200 and202 (FIG. 9) to arm 204 of a selector relay 206. Arm 204 is so arrangedthat it closes a circuit to wire 208 when selector relay 206 is at home(i.e. in its rest position). From wire 208, a current path is thereforeestablished through wire 210 and relay coil 212 to the other bus 214 ofthe power supply A-B. Relay 212 now becomes energized and locks itselfin by closing its normally open contacts 216. At the same time, theenergization of relay 212 closes its normally open contacts 218 and acurrent path is established from wire 210 through wire 220 and thenormally closed contacts 222 of relay 224. From there, current flowsthrough wire D to the home contact H of gang 226 of selector relay 206,and through selector arm 2128 and the (now closed) normally opencontacts 218 of relay 212 to the interrupter contacts 230 and steppingcoil of relay 206. The other end of the coil 206 is connected to thepower bus 214.

Due to the action of interrupter 230, selector arm 228 now starts totravel along the contacts of gang 226, each of which is connected to bus198 through one of the push buttons of keyboard 132, until it reaches acontact which is not connected to bus 198. The only such contact it ndsis contact 232 which is dead because push button 192 is depressed.Selector arm 228 no-w remains at contact 232. It should be understoodthat selector relay 206 is of the fast-acting type and reaches contact232 in less than half a second. When push button 192 is now released,bus 198 is cut off from bus 190 and the current to gang 226 of selectorrelay 206 is cut off. At the same time, the de-energization of bus 198deprives relay 212 of current, and relay 212 drops out, opening contacts216.

While the previously described process was going on, normally closedcontacts 234 of relay 212 :were open. As soon as selector arm 228 leftthe home position, switch arm 204 opened and switch arm 236 closed.Therefore, when relay 212 drops out, bus 198 becomes disconnected lfromwire 210 and instead becomes connected to wire 238. It will be readilyseen that if push .button 240 is now depressed, relay 242 will becomeenergized, closing contacts 244 and 246, and opening contact 248. Thiscauses selector relay 250 to become energized, and selector arm 252steps along the contacts of gang 2154 and comes to rest c-n Contact 256.Release of push button 240 causes wire 238 to become connected to wire258 through contact arm 260. `If push button 262 is now depressed, relay264 is energized, closing contacts 266 `and 268 and yopening contacts270. Selector arm 272 of selector relay 274 thereupon steps to contact1276, and the flight number 749 has now been fully set up. Release ofpush button 262 causes relay -264 to drop out, and contacts 270, uponreclosing, throw power through switch arm 278 and wire 280 onto relay188. Energization yof relay -188 causes contacts 186 to open, thusdisabling the keyboard, `and contacts 282 (FIG. 10) to close, thuslighting the ready light 284 iff limit switches 286 and -288 are closed,as they normally are when a tray is in the release position 662 of scale690 (FIG. 4) and lift 672 is in position to receive a tray. With theencoder in this condition, it is now possible to release a `tray intothe encoder by pressing release button 134 on .console 124. Section 290(FIG. 9) of release button 134 disables the cancel button until relay296 (FIG. l) has had time to open its contacts 314 (FIG. 9) for the samepurpose. Section 294 (FIG. l0) operates the gate mechanism 292 whichstarts a `tray 100 on its way.

The gate 292 is so arranged in a well-known manner as to re-oloseimmediately atte-r the tray clears it, as e.g. by actuation of a limitswitch 692, and not to release another tray until wire i304 isde-energized and then reenergized.

At the same time, section 294 of release button 134 energizes relay 296through normally closed contacts 298 and ready switch 300. IEnergizationof relay 296 causes contacts 298 to open, and contacts 302 to closeinstead. This causes relay `296 -to lock itself in until ready switch368 is opened by the return of lift `672 ('F-IG. 4) to itstray-receiving position. While relay 296 is energized, contacts 298(FIG. 10) extinguish the ready light 284 and instead contact 308 closesto light up the wait light 310. In this condition, all controls aredead, and no further release can take place until rlift 672 is ready toaccept another tray.

It Iwill be seen that in the circuit described, a code once set up willnot change unless it is purposely cancelled. This cancellation isaccomplished by pressing the cance button 184 (FIG. 5), whose twosections are shown in FIG. 10 at i182 and in rFIG. 9 at 3112. Section3112 of .the cancel button 184 is connected to bus 180 through thenormally closed contacts 314 of relay 296. Consequently, actuation ofthe cancel button while relay 296 is energized (i.e. when a tray ispassing through the encoder) has no effect. At other times, however,section 312 closes a circuit energizing relay 224. This causes contactsl316, 31'8 and 320 to close and contacts 222, 322 and 324 to open. As aresult, relays 212, 2142 and 264 are simultaneously tripped, andselector arms 228, 252 and 272 return to their home position. (In thiscondition, bus 198 is energized through contacts 316 and 216.) A write1ight326 is so connected to Ithe home contact of the indicator gang 332(FIG. 11) of selector relay 274 (discussed hereinafter) that it isilluminated whenever relay 274 is in the home position, i.e. until acomplete three-digit flight number has been written.

Referring now to FIG. 11, it will be seen that selector relay 274 hasIthree additional gangs 328, 330 and 332. (The other two selector relays`also have three `additional gangs which are connected in a like mannerand therefore not shown herein.) Selector `arm 334 of gang 328 isconnected to the power main y180 by wire 336. When selector relay 274stops in the position of contact 276 (FIG. 10), selector `arm 334 stopsat contact 338. In this position, it closes the circuit of relay 340,which in turn closes the normally open contacts 342 (FIG. 9) whichenable encoding coil 136n to function. IIn a like manner, selector arm344 of gang I330 energizes relay 346, which in turn closes contact 348,enabling the functioning of encoding coil .136k. Referring to FIG. 8, itwill be seen that energization yof coils `13611 and l136k will result inthe encoding `of the digit 9 of the night number 749. It will be readilyseen that in appropriate cases, relay 350 enables the energization ofcoil `136i through contact 352, and that relay 354 enables theenergization of coil 136m through contacts 356.

Switch arm 358 of gang 332 of selector relay 274 lights the write lamp326 in its home position, Iand lights the appropriate ligure onindicator tube 360, which forms part of the display 128 on the encodingconsole (FIG. 5), by grounding the appropriate cathode.

In the example chosen, the indicator tube 360 will show the figure 9,and contacts 348 and 342 will be closed. Transformer 362 meanwhilecharges capacitor 364 through rectifiers 366. When the tray is perfectlyaligned with encoding head -126, the leading bumper 114 of tray 100trips limit switch 306. This disconnects the primary of transformer 362from the power line and simultaneously short-circuits capacitor 364across busses 368 and 378 (which are common to all twelve coils 136,even though only four coils 136 are shown). This in turn causes thecapacitor 364 to discharge i.a. through coils 136k and 136n, these coilsbeing in the circuit because contacts 348 and 342 are closed.

It will be noted that because of 4the choice of binary designationsdescribed in Section 2.51.12, only two gangs of each selector relay arenecessary to set up any decimal digit on relays 340, 346, 350 and 354,or their equivalents for the Itens and hundreds digits. Also, the energyof capacitor 364 is distributed among no less than three nor more thansix coils 136 for any ight number from 000 to 999. This permits keepingthe intensity of the individual magnetic impulses within predeterminedlimits in spite of .the parallel connection of coils `136.

Because the tripping of limit switch 306 has disconnected the primary oftransformer 362, capacitor 364 cannot recharge until tray 100 has safelypassed out of the range of encoding head 126 and has released limitswitch 386 to its lower position.

Circuitry like that of FIG. l1 is duplicated for the hundreds and tensencoding apparatus associated with selector relays 206 and 250respectively. However, this circuitry is not shown herein so as not tounnecessarily complicate the drawings.

2.52-Spacer.-FIG. 28 schematically shows a section of conveyor in whichthe proper minimum spacing of trays is accomplished so that they willenter the decoding section at sufficiently long intervals to permitproper functioning of the decoding apparatus. Trays 100 enter FIG. 28from the right Iand travel to the left. The right-hand portion of theconvey-or 104 is equipped with rollers 380 powered by a belt 382. Thelast roller 384 in the chain of rollers 380 may be coated with rubber orother grip-

1. IN A MATERIALS HANDLING SYSTEM HAVING A RECIRCULATING MAIN CONVEYOR,AT LEAST ONE FEED CONVEYOR FEEDING THEREINTO, A PLURALITY OF BRANCHCONVEYORS EXITING THEREFROM, A PLURALITY OF MATERIAL CARRYING TRAYS, ANDMEANS FOR SELECTIVELY DIVERTING SAID TRAYS FROM SAID MAIN CONVEYOR TOSAID BRANCH CONVEYORS, THE COMBINATION COMPRISING: A LONGITUDINALLYPROTRUDING FLANGE ON THE SIDE OF EACH SAID TRAY, SAID FLANGE HAVING APLURALITY OF BISTABLE MAGNETIC SLUGS IMBEDDED IN ITS SURFACE ATPREDETERMINED INTERVALS; AN ENCODING STATION POSITIONED ALONG SAID FEEDCONVEYOR HAVING A WRITE HEAD WITH A LONGITUDINAL GUIDE SLOT ADAPTED TORECEIVE SAID FLANGE AND HAVING A PLURALITY OF ELECTROMAGNETIC WINDINGMEANS POSITIONED THEREALONG IN SUCH A MANNER THAT ONE SUCH WINDING MEANSAPATIALLY MATCHES EACH OF SAID SLUGS ON EACH SAID TRAY; MEANS FORGUIDING SAID FLANGE INTO SAID WRITE HEAD SLOT; MEANS FOR SELECTIVELYARMING CERTAIN OF SAID ELECTROMAGNETIC WINDING MEANS ACCORDING TO APREDETERMINED CODE WHICH IS INDICATIVE OF SOME CHARACTERISTIC OF THEMATERIAL CONTAINED IN ONE OF SAID TRAYS; MEANS FOR ACTIVATING SAID ARMEDELECTROMAGNETIC WINDING MEANS ONLY WHEN SAID WINDING MEANS AND THEIRRESPECTIVE MATCHING SLUGS ARE ADJACENT EACH OTHER WHEREBY THE SLUGS ONSAID ONE OF SAID TRAYS HAVE A MAGNETIC SIGNAL IMPRESSED THEREON WHICH ISINDICATIVE OF A CHARACTERISTIC OF THE MATERIAL IN THAT TRAY; A DECODINGSTATION POSITIONED ALONG SAID RECIRCULATING